[PATCH v3 02/10] KVM: MMU: introduce for_each_rmap_spte()

Xiao Guangrong
2015-05-13T06:46:11Z

It's used to walk all the sptes on the rmap to clean up the
code

Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
---
arch/x86/kvm/mmu.c | 53 ++++++++++++++++--------------------------------
arch/x86/kvm/mmu_audit.c | 4 +---
2 files changed, 19 insertions(+), 38 deletions(-)

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index d00cebd..afc8d15 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -1142,6 +1142,11 @@ static u64 *rmap_get_next(struct rmap_iterator *iter)
return NULL;
}

+#define for_each_rmap_spte(_rmap_, _iter_, _spte_) \
+ for (_spte_ = rmap_get_first(*_rmap_, _iter_); \
+ _spte_ && ({BUG_ON(!is_shadow_present_pte(*_spte_)); 1;}); \
+ _spte_ = rmap_get_next(_iter_))
+
static void drop_spte(struct kvm *kvm, u64 *sptep)
{
if (mmu_spte_clear_track_bits(sptep))
@@ -1205,12 +1210,8 @@ static bool __rmap_write_protect(struct kvm *kvm, unsigned long *rmapp,
struct rmap_iterator iter;
bool flush = false;

- for (sptep = rmap_get_first(*rmapp, &iter); sptep;) {
- BUG_ON(!(*sptep & PT_PRESENT_MASK));
-
+ for_each_rmap_spte(rmapp, &iter, sptep)
flush |= spte_write_protect(kvm, sptep, pt_protect);
- sptep = rmap_get_next(&iter);
- }

return flush;
}
@@ -1232,12 +1233,8 @@ static bool __rmap_clear_dirty(struct kvm *kvm, unsigned long *rmapp)
struct rmap_iterator iter;
bool flush = false;

- for (sptep = rmap_get_first(*rmapp, &iter); sptep;) {
- BUG_ON(!(*sptep & PT_PRESENT_MASK));
-
+ for_each_rmap_spte(rmapp, &iter, sptep)
flush |= spte_clear_dirty(kvm, sptep);
- sptep = rmap_get_next(&iter);
- }

return flush;
}
@@ -1259,12 +1256,8 @@ static bool __rmap_set_dirty(struct kvm *kvm, unsigned long *rmapp)
struct rmap_iterator iter;
bool flush = false;

- for (sptep = rmap_get_first(*rmapp, &iter); sptep;) {
- BUG_ON(!(*sptep & PT_PRESENT_MASK));
-
+ for_each_rmap_spte(rmapp, &iter, sptep)
flush |= spte_set_dirty(kvm, sptep);
- sptep = rmap_get_next(&iter);
- }

return flush;
}
@@ -1394,8 +1387,8 @@ static int kvm_set_pte_rmapp(struct kvm *kvm, unsigned long *rmapp,
WARN_ON(pte_huge(*ptep));
new_pfn = pte_pfn(*ptep);

- for (sptep = rmap_get_first(*rmapp, &iter); sptep;) {
- BUG_ON(!is_shadow_present_pte(*sptep));
+restart:
+ for_each_rmap_spte(rmapp, &iter, sptep) {
rmap_printk("kvm_set_pte_rmapp: spte %p %llx gfn %llx (%d)\n",
sptep, *sptep, gfn, level);

@@ -1403,7 +1396,7 @@ static int kvm_set_pte_rmapp(struct kvm *kvm, unsigned long *rmapp,

if (pte_write(*ptep)) {
drop_spte(kvm, sptep);
- sptep = rmap_get_first(*rmapp, &iter);
+ goto restart;
} else {
new_spte = *sptep & ~PT64_BASE_ADDR_MASK;
new_spte |= (u64)new_pfn << PAGE_SHIFT;
@@ -1414,7 +1407,6 @@ static int kvm_set_pte_rmapp(struct kvm *kvm, unsigned long *rmapp,

mmu_spte_clear_track_bits(sptep);
mmu_spte_set(sptep, new_spte);
- sptep = rmap_get_next(&iter);
}
}

@@ -1518,16 +1510,13 @@ static int kvm_age_rmapp(struct kvm *kvm, unsigned long *rmapp,

BUG_ON(!shadow_accessed_mask);

- for (sptep = rmap_get_first(*rmapp, &iter); sptep;
- sptep = rmap_get_next(&iter)) {
- BUG_ON(!is_shadow_present_pte(*sptep));
-
+ for_each_rmap_spte(rmapp, &iter, sptep)
if (*sptep & shadow_accessed_mask) {
young = 1;
clear_bit((ffs(shadow_accessed_mask) - 1),
(unsigned long *)sptep);
}
- }
+
trace_kvm_age_page(gfn, level, slot, young);
return young;
}
@@ -1548,15 +1537,11 @@ static int kvm_test_age_rmapp(struct kvm *kvm, unsigned long *rmapp,
if (!shadow_accessed_mask)
goto out;

- for (sptep = rmap_get_first(*rmapp, &iter); sptep;
- sptep = rmap_get_next(&iter)) {
- BUG_ON(!is_shadow_present_pte(*sptep));
-
+ for_each_rmap_spte(rmapp, &iter, sptep)
if (*sptep & shadow_accessed_mask) {
young = 1;
break;
}
- }
out:
return young;
}
@@ -4481,9 +4466,8 @@ static bool kvm_mmu_zap_collapsible_spte(struct kvm *kvm,
pfn_t pfn;
struct kvm_mmu_page *sp;

- for (sptep = rmap_get_first(*rmapp, &iter); sptep;) {
- BUG_ON(!(*sptep & PT_PRESENT_MASK));
-
+restart:
+ for_each_rmap_spte(rmapp, &iter, sptep) {
sp = page_header(__pa(sptep));
pfn = spte_to_pfn(*sptep);

@@ -4498,10 +4482,9 @@ static bool kvm_mmu_zap_collapsible_spte(struct kvm *kvm,
!kvm_is_reserved_pfn(pfn) &&
PageTransCompound(pfn_to_page(pfn))) {
drop_spte(kvm, sptep);
- sptep = rmap_get_first(*rmapp, &iter);
need_tlb_flush = 1;
- } else
- sptep = rmap_get_next(&iter);
+ goto restart;
+ }
}

return need_tlb_flush;
diff --git a/arch/x86/kvm/mmu_audit.c b/arch/x86/kvm/mmu_audit.c
index 9ade5cf..368d534 100644
--- a/arch/x86/kvm/mmu_audit.c
+++ b/arch/x86/kvm/mmu_audit.c
@@ -197,13 +197,11 @@ static void audit_write_protection(struct kvm *kvm, struct kvm_mmu_page *sp)

rmapp = gfn_to_rmap(kvm, sp->gfn, PT_PAGE_TABLE_LEVEL);

- for (sptep = rmap_get_first(*rmapp, &iter); sptep;
- sptep = rmap_get_next(&iter)) {
+ for_each_rmap_spte(rmapp, &iter, sptep)
if (is_writable_pte(*sptep))
audit_printk(kvm, "shadow page has writable "
"mappings: gfn %llx role %x\n",
sp->gfn, sp->role.word);
- }
}

static void audit_sp(struct kvm *kvm, struct kvm_mmu_page *sp)
--
2.1.0